Electric-wave-translation system



July 24, 1928. 1,678,160

A. A. OSWALD ELECTRIC WAVE TRANSLATION SYSTEM Filed March 20, 1924 Patented July 24, 1928.. a

UNITED STATES I PATENToFI-ICE.

ARTHUR 'A. oswALn, or RAsT OR NGE, NEW .mxsnr, ASSIGNOR To WESTERN ELEG- TRIGCOMPANY, mcoRroRATEn; or NEW YORK, N. Y., A ooRroRATIoN or NEW YORK.

ELECTRIO -WAVE-TRANSLA'IION SYSTEM.

Application filed March 20, 1924. Serial No. 702,558.

This invention relates to electric wave translation systems and more articularly to arrangements of space disc arge tubes whereby parasitic oscillations between tubes are revented.

W ere large numbers of power space d1scharge tubes are operated in parallel, the

tubes are usually arranged in groups forming units or banks to give flexibility, that is, for example, to enable a spare banl. to'

be substituted for another bank needing epairs without interference with the operation of the remaining tubes of the system. When tubes are arranged in this way it has been found that there is a tendency for singing or parasitic oscillations to be set up between banks. This phenomenon, known as inter-bank singing, is caused by energy fed back from output elements to control ele ments of the s stem through the inherent reactances of t e tubes themselves in com- .bination. with that of their connecting circuits in such manner as to produce sustained oscillations. This singing may also occur if the number of tubes in each bank is limited to ,one. It is therefore to be understood that a bank as referred to hereafter may comprise a single tube.

It is an object of this invention to prevent.

singing between tubes in a system of space discharge tubes having a plurality of banks.

Another object is to prevent the generation of parasitic oscillations in systems of space discharge devices comprising a plurality of pairs of banks.

A further object is to enable any number of banks to be out in or out of a space discharge tube system arranged to prevent inter-bank singin without interference with the operation 0 the rest of the system.

Generically, this invention comprises systems of plural electrode space discharge tubes arranged in banks having their control electrodes and anodes connected to a common input circuit and a common output circuit, respectively. The leads between banks connected to the electrodes may contain difierential devices which inone specific instance may be impedances consisting of inductances shunted by individual resistances to impede currents tending to flow between the banks. The common circuits are, however, differentially connected to the impedance devices in such manner that signal currents flowing through these circuits to the separate banks are not materially impeded.

In the drawings, Fig. 1 illustrates a radiant energy transmitting system including an odd number of banks of power tubes arranged to prevent inter-bank singing;

Fig. 2 illustrates an arrangement whereby nter-bank singing may be prevented between any number of banks of power tubes and whereby any bank may be switched in or out of the system;

Fig. 3 illustrates a method of connecting a plurality of pairs of power tube banks to prevent inter-bank singing.

Referring first to Fig. 1, a source'10 is arranged to supply waves through a trans- "former'21 to a power translation device 30 which is coupled to an antenna 50 by means of a. transformer 51. The waves produced by source 10 maybe of high or low frequency; they may be signal modulated waves or merely unmodulated power waves. The source 10 is connected tothe primary winding of transformer 21. Thesecondary winding of this transformer is included ,in a common input circuit oi the translation device or amplifier 30 in series with a polarizing battery 22 and an impedance network 34. The common input circuit is connected between the control electrodes and cathodesof the plural electrode space dis charge tubes 31, 32 and 33.

The output circuit of amplifier 30 is connected between the anodes and cathodes of tubes 31, 32 and 33 and includes the impedance network 36, blocking condenser 39, and a resonant circuit 41, 42. Space current is supplied to the tubes 31, 32 and 33 by means of generator 38 shunted by condenser 38 and connected between the choke coils 37.

The resonant circuit comprises condenser 41 and inductance 42. The inductance 42 --forms the primary winding of transformer 51. The secondary winding of this transformer is connected in series between the antenna 50 and ground. The antenna may be replaced by any type of load circuit such as a wire transmission line power distributing system, or other power receptor.

The polarizing battery 22 included 1n. the common input circuit of amplifier 30 is provided to impress a suitable average potential upon the control electrodes of the tubes 31, 32 and 33. The cathodes of tubes 31, 32 and 33 are all connected in parallel to a source of heating current 43 in series with an adjustable resistor 44.

The impedance networks 34 and 36 included in the input and output circuits are provided to prevent singing between the banks of tubes 31, 32 and 33.

The network 34 comprises inductances 45, 46 and 47 connected in series to form a closed loop. The junction points of these inductances are connected through switches 70, 71. and 72 to the control electrodes of tubes 31, 32 and 33 respectively, and-- also to individual resistances 55, 56 and 57. The opposite terminals of these resistances are connected to respective contacts of switches 58, 59 and 60 and to the midpoints of inductances 45, 46 and 47, respectively. The switch arms are all connected to the common lead extending to one terminal of the secondary winding of transformer 21. Switches 25, 26, 27 are arranged to short circuit their respective inductances when closed.

The impedance network 36 is identical in arrangement with that of 34. This network comprises the inductances 45', 46', and 47 the resistances 56', and 57, and the switches 58', 59' and 60', 25', 26 and 27', and 71' and 72'.

By operating the proper switches any one or any number of the banks 31, 32, 33 ma be cut in or out without interference wit the operation of the system. For example by opening switches 70 and 60 and by closing switch 25 of network 34 and the corresponding switches of network 36 bank 31 will be disconnected from the system and banks 32 and 33 will remain in operative condition.

The waves from source 10 are supplied through transformer 21 to the common input circuit of am lifier 30. The waves produced in this in t circuit flow to the control electrodes 0 tubes 31, 32 and 33, respectively, through inductances 45, 46, and 47. By means of battery 22, an average potential is applied to the control electrodes of tubes 31, 32 and 33, whereby the waves supplied to the input circuit are repeated in greatly amplified form in the output circuit of these tubes. The amplified current flows through the inductances 45', 46', and 47' to the commonlead' extendingto the output circuit including condenser 39 and resonant circuit 41, 42. This resonant circuit is tuned to the frequency of waves to be transmitted. Wave energy is thus supplied through transformer 51 to antenna 50 and radiated therefrom.

Undesired waves flowing between the grid electrodes of one bank and those of the other banks, or from the anodes of one bank to those of the other banks must pass through the impedance networks 34 or 36.

Coils 45, 46, 47 and 45, 46 and 47 are arranged to be substantially non-inductive for waves flowing in the common input circuit and the common output circuit respectively. But these coils are arranged to be inductive with respect to currents flowing between banks and therefore to impede the flow of these currents. Hence by providing shunting resistances around these coils the currents flowing between banks are caused to pass therethrough. The resistances are designed to dissipate the energy of interbank current sufficiently to prevent singing or parasitic oscillations from being produced. 1

The frequency of oscillations that may be set up between banks without the impedance networks 34 and 36 is determined by the constants of the circuit including the internal capacities of the tubes and the re actance of connecting leads. The introduction of the coils of the impedance networks in the paths between the banks lowers the natural period of the circuits and thus the frequency at which parasitic oscillations tend to occur. At the lower frequency the .condition for oscillation isless favorable.

The resistance elements provide dissipation aths of such magnitude that the feedback etween the output and the input elements is insufiicient to sustain oscillations. It is to be noted that a low impedance path is provided for waves from source 10 through the two halves of eachcoil of the networks 34 and 36.

network which may be connected in the anode or control electrode circuits of space discharge tube systems, suchas shown in Fig. 1, having any desired number of banks of space discharge tubes.

Blocks 52 represent banks of space discharge tubes, the anodes or control electrodes of which may be connected to the leads extending to switches 53 respectively. The arms of switches 53 connect to the junction points of inductances 54 which are connected in series to form a closed loop. Each inductance is shunted by a switch 55, whereby it may be rendered inoperative by being short-circuited. I

The junction points between inductances 54 are connected to respective resistances 56 in series with associated condensers 59. The opposite terminals ofthese resistances are connected to respective contacts of switches 57 and to individual taps on the mid oints of the inductances 54. The arms of switches 57 are all connected together and are arranged to be connected to a lead 1n the common input or common output clrcultsof the banks of the tubes 52.

By means of the switches 53, and 57,-;

any one or any number of the banks of tubes 52 may be cut out of the system without d1sturbing the operation of the remaining banks of tubes.

. The impedance network of Fig. 2 functions in a manner identical with that explained in connection with network 34 and 36 of Fig. 1. The condensers 59 connected in series with resistances 56 are designed to have low impedance for waves of undesired frequency and to have high impedance for waves of desired frequency. These condensers thus aid in preventing desired waves from traversing theresistance path and being dissipated therein and aid in causing them to pass through the coils 45, 4:6, 47 and 45'. 4.6, and 47'.

an impedance network 66 comprising inductances 67 shunted by resistances 68.

The operation of these networks is the same as that of the networks described in connection with Figs. 1 and 2. The inductances 67 in each network ofier a large impedance to currents tending to flow between associated banks of tubes or between associated pairs of banks of tubes as the case may be, hence thesecurrents are: compelled to flow through the high resistances 68 which act to suppress and to dissipate the energy of these currents.

On the other hand, the currents flowing in the common circuit connected to lead in parallel to the banks of tubes 61,- 62 and 63, 64 pass through the halves of inductances 67 in such manner that very small impedance is offered thereto. This arrangement is applicable to larger groups of banks in pairs by multiplying the number of banks each time by two.

Although this invention has been described in connection with certain specific embodiments, it maybe employed in numerous other ways clearly within its scope. The invention is therefore to be limited only as defined in the appended claims.

What is claimed is:

1. In a space discharge tube: system including a number of units greater than two pressing oscillations each unit comprising one or more tubesand common paths for desired and undesired waves, the method of preventin *the trans,- mission of waves of undesire frequency between-units in said system which comprises causing waves of desired frequenc. to traverse said common aths in paralle and causing waves of un esired frequency to traverse said paths in series.

2. Inaspace discharge tube system comprising a plurality of units connected in parallel, each. unit including one or more space discharge tubes and means individual to said units for rendering certain if the tubes thereof inoperative and maintaining the remaining tubes continuously operative, the method of preventing the production of waves of undesired frequency in the system which comprises causing waves of desired frequency to traverse a direct current con ductive path therefor, excluding waves of undesired frequency therefrom, and dissipat-ing waves of undesiredfrequency in a path connected to said direct current conuctive path.

3. In a space discharge tube system com prising a multiplicity of banks of space discharge tubes, reactive paths between banks and dissipative paths between banks, said reactive paths being traversed by desired and undesired waves, the method of preventing interbank singing which comprises causing said desired waves to traverse portions of said reactive paths in .parallel and causing undesired waves to traverse said dissipatlve paths 1n serles.

4. In a space discharge system comprising an odd number of parallel connected space disrharge units, the method of preventing the production of undesired oscillations in the system which comprises causing oscillations of desired frequency to traverse a conductive path therefor and causing oscillations of undesired frequency to be diverted into a dissipative path in shunt to the conductive path.

5. In a space discharge system including a plurality of parallel connected space discharge units inc uding electrodes, the method of preventing the production of undesired oscillations in the system which comprises causing oscillations of desired frequencies from the respective units to traverse parallel conductive paths with respect to the cone sponding electrodes of said units, and imof undesired fre quencies upon a path including in series a condenser to control the suppression of said undesired oscillations.

6. Av space discharge system comprising an odd number of space discharge units having electrodes, means adapted to provide to provide series dissipative paths between corresponding electrodes, for undesired waves.

7. A space discharge system comprising a lurality of space discharge units, means or connecting said units in parallel relatively to an external circuit, means for cutting in or out of the system any number of said units without interference with the operation of the remaining units of the system, and an impedance network comprising branches having resistances for dissipating the energy of waves of undesired frequency whereby the production of parasitic oscillations is prevented.

8. A space discharge system comprising a plurality of units, each including three electrode space-discharge devices, a reactance element having its terminals connected to the corresponding electrodes of said units and its midpoint connected to an external circuit, and means for connecting or disconnecting one or more of said units from said network without interference with the operation of the remaining units.

9. A space, discharge system comprising an odd number of units each including three.

electrode space discharge devices, a common input circuit and a common output circuit for said devices, a reactance device in each of said circuits comprising inductances and resistances connected in parallel having their terminals connected to the correspondin electrodes of said device, and their mid- POlIltS, connected to an external circuit.

10. In combination in an electric energy banks, an impedance network comprising inductances connected 1n series .to form a closed loop, individual connections between the junction points of said inductances and said banks, a plurality of branch circuits also connected to said junction points, said branch circuits each including a capacity and resistance, each of said branch circuits having means for connecting or disconnecting it to a common terminal, a plurality of switching means for shortcircuiting any one or all of said inductances, said impedance network acting to prevent the production of undesired oscillations in said system.

11. In an electric energy translation systern, a source of waves, a space discharge amplifier supplied with said waves, said amplifier gomprising a plurality of space distharge tubes arranged in an oddnumber of banks, said space discharge tubes comprising control electrodes and anodes, said control electrodes being connected to a common input circuit and said anodes being connected to a common output circuit, said input and output circuits comprising impedance networks including inductances delta-connected to said control electrodes and anodes respectively and resistance elements star-connected to said control electrodes and anodes respectively whereby the production of undesired oscillations in said system are prevented, said network comprising in addition, means for rendering inoperative any one of said elements.

' In witness whereof, I hereunto subscribe -my name this 7th day of March A. D., 1924. translation system, a plurality of plural eleC- trode space discharge tubes arranged in ARTHUR A. OSWALD, 

